27 May Baldassarre's XX Corps was to attack the Bir Hakeim box to prevent the French Brigade interfering to the main attack together with the
Afrika Korps (
Generalleutnant Walter Nehring). The 15th and 21st Panzer divisions, the rest of the 90th Light Division and the "Ariete" Division began their large encircling move south of Bir Hakeim as planned. While some German tanks were in the area at the start of the battle none participated as they were ordered to go south by Rommel. The
3rd Indian Motor Brigade was surprised at on 27 May and overrun at Point 171, south-east of Bir Hakeim, by the
132nd Tank Infantry Regiment of the "Ariete" Division, losing about and most of its equipment. The 7th Motor Brigade was then attacked at Retma and forced back to Bir el Gubi. The 4th Armoured Brigade advanced in support and collided with the 15th Panzer Division; the 8th Hussars were destroyed and the 3rd Royal Tank Regiment (3rd RTR) lost many tanks. The British inflicted considerable losses in return but then retired to El Adem. After over-running the 3rd Indian Motor Brigade, the
VIII Tank Battalion M13/40, IX Tank Battalion M13/40 and
X Tank Battalion M13/40 of the 132nd Tank Infantry Regiment moved to the north-east of Bir Hakeim and the IX Battalion (Colonel Prestisimone) with 60 tanks, changed direction towards the fort. The IX Battalion arrived before the Bir Hakeim minefield and barbed wire at charged and lost and a self-propelled gun. Ten tanks got through the minefield and were knocked out by guns, causing casualties. The remnants of the IX Battalion retired to the main body of the "Ariete" Division, which moved north towards Bir el Harmat around noon, following Rommel's original plan.
28–30 May On 28 May, the
Desert Air Force (DAF) made a maximum effort to attack Axis columns around El Adem and Bir Hakeim but in the poor visibility, bombed Bir Hakeim and its surroundings, misled by the Italian tank wrecks around the position and Kœnig sent a detachment to destroy the wrecks to avoid any more mistakes. A French column was sent to make contact with the
150th Infantry Brigade, stationed further to the north. After a few hours, Italian artillery forced them to retire but the French column destroyed seven half-tracks. On 29 May, the detachment of
Gabriel de Sairigné destroyed three German tanks, British air attacks intercepted two raids by
Junkers Ju 87 () dive-bombers and fighter-bombers attacked Axis supply lines south and east of Bir Hakeim. On 30 May, from the 3rd Indian Motor Brigade, captured by the Axis and then released in the desert, reached the fort and added to the already there, making the
water shortage worse. The detachment of Lamaze, at the request of the
7th Armoured Division, sealed off the breach opened the day before by the Axis tanks in the minefields. Led by Colonel
Dimitri Amilakhvari, the legionnaires were ambushed but managed to retreat with the help of the Bren carriers of the 9th Company ().
31 May–1 June On 31 May, during a two-day sandstorm, fifty supply trucks of the 101st Transport Company ( Dulau), reached Bir Hakeim with water and took the Indians, prisoners and seriously wounded back to the British lines. A raid by the detachments , and , led by Amilakhvari, destroyed five tanks and an armoured vehicle repair workshop. The had been forced to retreat westwards, to an area north of Bir Hakeim, which became known as the Cauldron, having attacked the 150th Infantry Brigade box since 28 May. During the day, the DAF lost fifteen fighters and a bomber, combat with Axis fighters and one to
flak, the worst daily loss of the battle; the lost nine aircraft. On the west side of the Cauldron, the 150th Infantry Brigade was overrun late on 1 June, despite British relief attempts. The Axis troops that had been trapped gained a supply route through the Eighth Army minefields north of Bir Hakeim and next morning the encirclement of the fort was resumed by the 90th Light Division,
Trieste Division and three armoured reconnaissance companies from the
17th Infantry Division "Pavia". At German troops approached from the south and Italian forces advanced from the north. Two Italian officers presented themselves at to the 2nd Foreign Legion Battalion lines, asking for the capitulation of the fort, which Kœnig refused.
2–4 June From on 2 June, both sides exchanged artillery fire but the French field guns were out-ranged by German medium artillery and the fort was bombed by German and Italian aircraft. dive bombers raided Bir Hakeim more than twenty times but the French positions were so well built as to be almost invulnerable. The British were unable to reinforce the French, who repulsed the "Ariete" Division attack but on 2 June, the DAF had an easily observed bomb line around the fort and concentrated on the area with fighter patrols and fighter-bomber attacks. The sight of scores of burning vehicles helped to maintain the morale of the defenders, who harassed Axis communications around the fort, as did the 7th Motor Brigade and the 29th Indian Infantry Brigade which were in the vicinity. On 4 June, DAF fighters and fighter-bombers disrupted Stuka attacks and bombed Axis vehicles, blowing up an ammunition wagon in view of the French but losing seven aircraft. Kœnig signalled Air Vice-Marshal
Arthur Coningham. "" which brought the reply "".
5–7 June From 5 to 6 June, the DAF flew fewer sorties at Bir Hakeim, concentrating on the Knightsbridge Box and around on 6 June, the 90th Light Division attacked with the support of pioneers to try to clear a passage through the minefield. The pioneers got within of the fort, having breached the outer minefield and during the night they managed to clear several passages into the inner perimeter. German infantry gained a foothold but the French troops in foxholes, dug outs and blockhouses, maintained a great volume of small-arms fire, which forced the Germans under cover. Operation Aberdeen, an attempt to destroy Axis forces in the Cauldron, which had begun on the night of was a . Ritchie considered withdrawing the French from the fort to release the 7th Motor Brigade but decided to keep possession and on 7 June, four DAF raids were made against the Germans in the minefields. That night, a last convoy approached the fort and Bellec got through the German lines, in thick fog, to guide the convoy in. The Germans used the fog to prepare a final assault; tanks,
88 mm guns and the pioneers of formed up in front of the fort.
8–9 June On the morning of 8 June, after the defeat of Operation Aberdeen, Rommel had released part of the 15th Panzer Division and for the siege. Rommel commanded an attack from the north, approaching as close as possible in thick fog, with artillery firing directly against the fortifications. The made constant attacks, including a raid by
Stukas, three ten
Messerschmitt Bf 110 twin-engined fighters escorted by Just before the attack began, aiming at a low rise which would overlook the French defences. The
Chadian and
Congolese defenders held on despite many casualties and in the afternoon another 60 bombed the perimeter and an attack was made all round the northern defences. An ammunition dump was blown up and the perimeter forced back. Kœnig reported that the garrison was exhausted, had suffered many casualties and was down to its reserve supplies; he asked for more air support and a relief operation. The DAF made another maximum effort, flew a record and during the night,
Hawker Hurricane fighters and
Douglas Boston bombers dropped supplies to the garrison. The DAF lost eight fighters (three to Italian
Macchi C.202s) and two bombers; the lost two aircraft and the one. On the morning of 9 June, 20 40 escorted by 50 Bf 110 and
Bf 109 fighters, attacked Bir Hakeim. The Germans waited for the rest of the 15th Panzer Division to arrive as German artillery and aircraft bombarded the fort, then a two-pronged attack struck the perimeter. Italian infantry fought alongside , the German and Libyan infantry of (Special Commando 288) from the 90th Light Division, elements of the reconnaissance and infantry units of 15th and 21st Panzer Divisions and a company of 11 tanks. The objective was Point 186, the top of a gentle rise in the ground which acted as a fire-control position for the garrison. A few skirmishes occurred between the
66th Infantry Regiment "Trieste" of the "Trieste" Division and the men commanded by Lieutenant Bourgoin, whose unit was down only to hand grenades. The made a determined defence but was forced back, despite reinforcements of the 22nd North African Company. In the afternoon, to the south, near the old fort,
Ernst-Günther Baade led two battalions of Rifle Regiment 115 into the assault and in a costly advance, it established a position of the fort by nightfall. At as bombed the north face of the fort, the German infantry and the 15th Panzer Division attacked behind an artillery barrage. The attackers breached the 9th Company lines and the central position of Morvan but the situation was restored with a Bren carrier counter-attack. Many DAF aircraft were unserviceable and the effort for the day was much reduced but two Hurricanes dropped medical supplies; diversions attempted by columns from the 7th Motor Brigade and the 29th Indian Infantry Brigade were too small to have much effect. In the afternoon Messervy, the commander of the 7th Armoured Division, signalled that a break-out might be necessary and Kœnig asked for DAF protection for an evacuation at that night. The request was made at too short notice and the garrison had to wait until the night of 10/11 June for a rendezvous to be arranged by the British to the south.
Retreat, 10–11 June During 10 June, the French hung on and suffered many casualties; with only two hundred and rounds left, another attack on the northern sector against the Oubangui-Chari and 3rd Foreign Legion Battalion lines was contained by a counter-attack by the Messmer and Lamaze units, supported by Bren carriers and the last mortar rounds. In the afternoon, the biggest air attack of the siege, a raid by 100 dropped of bombs. The last rounds of ammunition were issued and bodies searched for more; Rommel predicted that Bir Hakeim would fall the next day but resisted pressure to attack with tanks, fearing that many would be lost in the minefields. As darkness fell,
sappers began to clear mines from the western face of the fortress, heavy equipment was prepared for demolition and two companies were detailed to stay behind to disguise the retirement. A rendezvous was arranged with the 7th Motor Brigade, which ran a convoy of lorries and ambulances to a point south of the fort. Mine clearance by the sappers took longer than expected and they were only able to clear a narrow passage, rather than a corridor. Vehicles went astray and the ambulances and walking-wounded left the perimeter late at Kœnig put the fort under the command of Amilakhvari, the Foreign Legion commander and left the fort at the head of the column in his Ford, driven by
Susan Travers, an Englishwoman, the only female member of French Foreign Legion (and one of several women, mostly British, present at the siege). A flare rose and the Axis troops nearby opened fire. The guide of the HQ column got lost and during the retirement was blown up three times by mines. When Kœnig caught up with the main column, it was blocked by troops of the 90th Light Division and he ordered a rush, regardless of the mines; Lamaze,
Charles Bricogne and Lieutenant Dewey were killed in the . The reception was organised by
Royal Army Service Corps (RASC) which drove lorries and guided extra field ambulances, with inexperienced rear-area crews, escorted by the 2nd
King's Royal Rifle Corps (KRRC) and the 2nd Rifle Brigade on either side. The ambulances became separated in the dark but were found and guided to the rendezvous. The commander of the 3rd Battalion was captured but most of the brigade managed to break out, reach Bir el Gubi, then withdraw to Gasr-el-Arid by on 11 June. About of the original escaped, including during the day British patrols picked up stragglers. ==Aftermath==